Modeling biomass allocation strategy of young planted Zelkova serrata trees in Taiwan with component ratio method and seemingly unrelated regressions

Abstract

Trees accumulate biomass by sequestrating atmospheric carbon and allocate it to different tree components. A biomass component ratio is the ratio of biomass in a tree component to total tree biomass. Modeling the ratios for Zelkova serrata, an important native reforestation tree species in Taiwan, helps in understanding its biomass allocation strategy to design effective silvicultural treatments. In this study, we applied Component Ratio Method (CRM) to relate biomass component ratios of main stem, large branch, twig, and foliage to tree attributes of Z. serrata from a 9-year-old plantation. Nonlinear and linear CRM models were fitted with Seemingly Unrelated Regression to account for model correlations. Linear CRM models with dbh as the predictor had the best fit with model correlations as high as 80%. About 46% and 40% of total tree biomass was allocated to main stem and large branch, respectively. However, main stem biomass decreased by 1.9% with every 1-cm increase in dbh, but large branch biomass increased by 2.2% instead. Results suggest that dominant Z. serrata trees tend to branch and fork, while smaller trees invest in larger main stem. An early pruning treatment should focus on dominant trees to maintain crown ratio and ensure wood quality.

Effects of Elevation, Stand Density, and Inter-Tree Competition on Tree Sizes, Vulnerability, and Health of Planted <i>Zelkova serrata</i> and <i>Quercus glauca</i> in Reforestation

“…This may be due to different growth strategies between the two species. Chen et al (2021) showed that a nine-year old single species Z. serrata plantation displayed significant stratification in stand structures due to strong inter-tree competition. In early stand development, dominant Z. serrata trees quickly reach upper strata by investing greater energy in crown development (Chen et al 2021).…”

“…Chen et al (2021) showed that a nine-year old single species Z. serrata plantation displayed significant stratification in stand structures due to strong inter-tree competition. In early stand development, dominant Z. serrata trees quickly reach upper strata by investing greater energy in crown development (Chen et al 2021). As a result, dominant Z. serrata trees develop large crowns, which in turn leads to rapid diameter and height growth.…”

“…As a result, dominant Z. serrata trees develop large crowns, which in turn leads to rapid diameter and height growth. On the other hand, Z. serrata trees that are suppressed due to inter-tree competition sacrifice crown development in favor of growing main stem (Chen et al 2021). This strategy perhaps allows suppressed Z. serrata trees to persist under greater inter-tree competition.…”

“…Z. serrata commonly distributes between 300 to 1000 m a.s.l. and is desired for its ability to sequestrate carbon during early stand development (Chen et al 2021). Q. glauca distributes between 500 and 1500 m a.s.l.…”

Green Public Areas and Urban Open Spaces Management: New GreenCAL Tool Algorithms and Circular Economy Implications

“…Particular attention was taken to avoid a dense plantation scheme [48]. The prescribed number of living plants per m 2 must be clearly indicated as well as their typology [59]. Specific climatic and soil conditions should be also taken into account, as the reforestation model must consider the different regions where it is applied and carefully select the autochthonous vegetation [60].…”